1. Field of the Invention
This invention relates to a compact chemical reactor and a system constituted of compact chemical reactors.
2. Description of the Related Art
In the technical field of chemical reactions, a chemical reactor is known which produces a desired fluid material by a chemical reaction of a fluidized mixture in the presence of a catalyst provided in a flow path. In such a chemical reactor, a groove, which becomes a minute flow path on a silicon substrate, is formed using a semiconductor integrated circuit micro working technique.
FIG. 16 is a plan view of an example of such a compact chemical reactor, and FIG. 17 is a sectional view along the line XVII—XVII of FIG. 16. This compact chemical reactor comprises a compact silicon substrate 1. In one surface of the silicon substrate 1, a minute meandering groove 2 is formed by use of the micro fabrication technique accumulated by the semiconductor production technique. A catalyst layer 3 is provided on an internal wall surface of groove 2.
A glass plate 4, which is to be a cover, is joined onto one surface of the silicon substrate 1. An inflow port 5 and an outflow port 6 which pass through the glass plate 4 in a thickness direction of the glass plate 4 are formed at two predetermined positions of the glass plate 4 corresponding to both ends of the groove 2.
Next, one example of a method for forming the groove 2 on the silicon substrate 1 of this chemical reactor will be described. First, as shown in FIG. 18, the meandering minute groove 2 is formed in one surface of the compact silicon substrate 1, by use of the micro fabrication technique. Next, a photoresist pattern 11 having an aperture 12 at a portion corresponding to the groove 2 is formed by applying a photoresist to one surface of the silicon substrate 1 including the inner surface in the groove 2 and then patterning this photoresist.
Next, the catalyst layer 3 is formed on the inner surface of the groove 2 and on a surface of the photoresist pattern 11 including an inner peripheral surface of the aperture 12. Then, as shown in FIG. 19, the photoresist pattern 11 is removed together with unnecessary portions of the catalyst layer 3 formed on an upper surface of the photoresist pattern 11, and as shown in FIG. 20, the catalyst layer 3 remains only on the inner wall surface of the groove 2. In this case, the photoresist pattern 11 is removed by a method using an exfoliation liquid or a method based on oxygen plasma ashing.
In the production method described above, when the photoresist pattern 11 is removed together with the unnecessary portions of the catalyst layer 3 formed on an upper surface of the photoresist pattern 11 using the exfoliation liquid, the catalyst layer 3 remaining on the inner wall surface of the groove 2 might be damaged by contact with the exfoliation liquid, and the catalyst layer 3 formed on the surface of the photoresist pattern 11 becomes an obstacle to prevent the exfoliation liquid for the exfoliation of the photoresist pattern 11 from sufficiently reaching the photoresist pattern 11, thus posing a problem that the photoresist pattern 11 sometimes cannot be removed satisfactorily. Alternatively, when the photoresist pattern 11 is removed together with the unnecessary portions of the catalyst layer 3 formed on the upper surface of the photoresist pattern 11 by the oxygen plasma ashing, the shadow of the catalyst layer 3 formed on the surface of the photoresist pattern 11 prevents a plasma seed from sufficiently reaching the photoresist pattern 11, thus posing a problem that the photoresist pattern 11 sometimes cannot be removed satisfactorily. Even if the photoresist pattern 11 can be removed satisfactorily, protrusions 3a of the catalyst layer 3 contacting the inner peripheral surface of the aperture of the photoresist pattern 11 remain as shown in FIG. 20, which will be an obstacle when the silicon substrate 1 and the glass plate 4 are joined, and thus the protrusions 3a are crushed to enter an interface portion 1a between the silicon substrate 1 and the glass plate 4 if they are forced to engage with each other, which produces a clearance between them, thus posing a problem that it is difficult for the groove 2 to allow a fluid flow without leakage.
Therefore, an advantage of this invention is that the photoresist for forming the catalyst layer in the groove that becomes the flow path can be removed satisfactorily without damaging the catalyst layer remaining in the groove.